Process of making smokeless powder.



Nn. 652,455. Patented lun 26, |900.- B. BEnNAnou. PROCESS UF MAKING SMOKE LESS POWDER.

(Application led Noi. 17, 189B.)

Anl. Q d n n. www.

A" UNITED STATES JOHN B. BERNADOU, OE THE UNITED STATES NAVY.

PROCESS OF MAKING SMOKE-:LESS POWDER.

SPECIFICATION forming part of Letters Patent N o. 652,45 5, dated J' une 26, 1900.

Application filed November 17,1898. Serial No. 696,725. (No specimens.)

T0 @ZZ whom it may concern.-

Beit known that I, Jol-IN B. BERNADOU, lieutenant, United States Navy, at present stationed in the city of W'ashington, District of Columbia, have invented certain new andY manufacture of colloid smokeless powders to' mix the nitro-cellulose with a colloiding agent, as acetone or ether alcohol, to place these materials in a mechanical mixer, in which they are thoroughly mixed, and to then form the resultant pasty` mass into the desired shapes, as rods, strips, or grains, which are then exposed to the air or to a moderate heat until the excess of solvent is expelled. The drying must be conducted with care and uniformity. If the powder be dried too quickly, as by exposure to too great a heat, the surface of the grains will be formed into a pellicle, while part of the interior content of the solvent will vaporize, causing the grain to swell and split. If the powder be not dried uniformly, the damper grains will ignite more slowly than the dryer ones, and hence irregularity in ignition and in ballistic performance will result. If the powder be left in an undried state, the traces of water, alcohol, and ether remaining in it operate to render it, in comparison with other lots of the same powder properly dried, slow in ignition.

Experience has shown that the complete and uniform drying of the colloid must be eected if the resultant mass is to prove a effective powder. The more effectually that the residual solvent, that remaining after the pasty colloid has been formed into the final shape, can be driven off the more efficient will be the powder, the greater its ballistic power, and the less the chance of hang-lires. The solvent commonly employed in the manufacture of smokeless powders is ether alcohol, which varies from a mixture of about two parts, by weight, of ether to one of alcohol, to amixture of about one part, by weight, of ether to two of alcohol. Thus in' specifications issued by the United States Navy Department a ratio of sixty-four parts,by weight, of ethyl ether to thirty-six parts, byweight, of ethyl alcohol is called for. On the other hand, the form of soluble nitro-cellulose employed for this powder, known as pyro-cellulose, is soluble ina mixture of two parts, by weight, of ethyl alcohol and one part, by weight, of ethyl ether, and for any mixture between these limits colloidization can be readily effected. In the processes hitherto in use further reduction in the relative amount of alco- -hol employed with the ether than that stated,

thirty-six parts of alcohol to sixtyfour of ether, by weight, tends to make the nitroconducted at ordinaryatmospheric tempera-v The addition of large quantities of tures. alcohol, which is permitted to contain as much as 7.7 per cent of water, by weight, necessarily introduces a considerable amount of water.

into the powder, andl this water is very difficult to get rid of.

I have discovered that if ether-alcohol-soluble nitro-cellulose be immersed in ethyl ether and be then exposed to a temperature of about that of freezing water or lower the nitro-cel-V lulose will go into solution or form a jelly with the ether, resulting in the formation of a upon application ofcold is commento all forms of soluble nitro-celluloses. By t soluble nitro-cellulose I mean those nitro-,celluloses L that will go into solution at ordinary atmos-f by weight,

f; l i 652,455

pheric temperatures in a mixture of two parts, by weight, about,) of ethyl ether and one part,

abouu) of ethyl alcohol. The property above referred to is possessed by soluble nitro-hydro-cellulose prepared by nitrating hydro cellulose, while the form of soluble nitro-cellulose known as pyro-cellulose, prepared by the hot process of nitration, also possesses the same property.

Ordinary forms of soluble nitro-celluloses prepared under the old process, which have been unduly heatedor treated with'alkali, causing partial disintegration or modification of their substance, display the phenomenon imperfectly, yet will colloid in ether sufficiently'under the infiuence of cold to illustrate the principle.

i The phenomenon of the action of the ether upon the nitro-cellulose maybe illustrated in a very'perfect manner by placing the soluble nitro-cellulose-for example, a gram of dry soluble nitro-hydro-cellulose, defined abovein aV testtube, adding an excess of ether, tightly corking it, and immersing it in a freezin g mixture of salt and ice. The soluble nitrocellulose, which at first remained undissolved like so much paper-pulp at the bottom of the clear ether, goes into solution under influence of the cold, producing a syrupy but mobile liquid. If the tube be now removed from the cooling mixture and warmed by immersion in lukewarm Water or even by being held tightly in the palm of the hand, the contents will congeal under inliuence of the heat into a dense jelly which will not obey the law of liquid iiow. Reimmersion of the tube into the cooling mixture will again render its contents liquid, and the alternaterendering of its contents liquid and solid may be effected by alternate rexposures to sources of cold and heat, respectively.

The heating on the above experiment is resorted to to illustrate the principle of the process--viz., that soluble nitro-cellulose is more soluble in the cool than in the warm liquid. If the tube be now uncorked and the excess of solvent be evaporated oif, a colloid will be formed which may be used as a smokeless powder or as a cementing agent for binding together otheringredients of smokeless powders.

The easewith which the soluble nitro-cellulose can be colloided in the presence of cold is materially increased by mechanical agitation-that is, by kneading or incorporating the ether and soluble nitro-cellulose together in'a closed vessel, whereby the colloid can be developed with the expenditure of 'a minimum amount of solvent. Y The process of forming the colloid powder, therefore, consists in subjecting the ether and soluble nitrocellulose to mechanical agitation or kneading insome approved form of mechanical mixer,

f such as' the ferner and Plieiderer, in the presence of a sufficient degree of coldand in subsequently removing the'mass after colloidization has ensued, forming into shapes or grains, and drying.

In the accompanying drawing I have illustrated the Werner and Piieiderer apparatus, a being the vessel in which the mixing takes place; b, blades which are revolvedin any suitable manner; c, a cover, and d a jacket adapted to contain a cooling mixture.

The cooling-jacket may be simply a cool atmospheric envelop in which the vessel a is placed.

Some nitro-celluloses are more refractory than others-that is, require more cold to produce colloidization. The addition of a small quantity of alcohol in such cases, say up to five per cent., will facilitate colloidization at temperatures below but near the freezingpoint.

In a division of this application, Serial No. 739,654, filed December 8, 1899, the colloid itself is claimed, the present application being confined to the process for makin g the colloid.

1. The described method of forming a colloid consisting in subjecting soluble nitrocellulose and a colloiding agent to a temperature equal to or below that of freezing water and in evaporating oft the excess of solvent in the resultant product.

2. The described method of forming a colloid consisting in subjecting soluble nitrocellulose and a colloiding agent, in a closed vessel, to a temperature equal to or below that of freezing water and in evaporating off the excess of solvent in the resulting product. 3. The described process of manufacture of a colloid powder, which'consists in subjecting soluble nitro-cellulose and a colloiding agent, in a closed vessel, to a temperature I equal to or below that of freezing water, me-

chanically agitating or kneading the cooled mixture, forming it into shapes or grains, and drying.

4. The described method of forming a colloid consisting in subjecting soluble .nitrocellulose and ether to a temperature equal to or below that of freezing water and in evaporating off the excess of solvent in the :resultant product.

5. The described method of forming a colloid consisting in subjecting soluble nitrocellulose and ether, in a closed vessel, to a temperature equal to or below that of freezing water and in evaporating olf the excess of solvent in the resultant product.

6. The described process of manufacture of a colloid powder, which consists in subjecting soluble nitro-cellulose and ether, in a closed vessel, to a temperature equal to or below that of freezing water, mechanically agirating or kneading the cooled mixture, form.- ing it into shapes or grains and drying.

JOI-IN B. BERNADOU.

Witnesses:

GEORGE W.1SELTZEE, CHARLES A. BUTTER.

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